The present invention relates to power supply units, and more particularly the present invention relates to a power-saving power supply unit for a computer system which automatically shuts off as the computer system does no work after a certain length of time.
A computer system has a power supply unit to provide a stable working voltage. The power supply unit produces heat when gives a stable working voltage to the computer system. After a continuous long use, the electronic component parts of the mainframe of the computer system may be damaged by the heat of the power supply unit easily. Therefore, radiating fins, mini fans, and other heat dissipating devices are used for dissipating the heat of the power supply unit. These heat dissipating techniques can not completely dissipate the heat of the power supply unit out of the computer system. Further, the power supply unit is constantly electrically connected as the power switch of the computer system is switched on, and therefore much power supply is wasted as the computer system does no work. The service life of the electronic components will be shortened if continuously provides electricity to the electric circuit of the computer system as the computer system does no work.